function writeCookie(name,value,days){
	var expires="";
	
	if(days){
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		expires = "; expires="+date.toGMTString();
	}
	
	document.cookie = name +"="+escape(value)+expires+"; path=/";
}

function eraseCookie(name){
	writeCookie(name,"",-1);
}

function readCookie(name){
	var searchName = name+"=";
	var cookies = document.cookie.split(';');
	for(var i = 0;i<cookies.length;i++){
		var c = cookies[i];
		while(c.charAt(0)==' ')
			c=c.substring(1,c.length);
		if(c.indexOf(searchName)==0)
			return  c.substring(searchName.length,c.length);
	}
	return null;
}